1. Field of the Invention
The present invention relates to display devices, and more particularly to a mother substrate of an organic light emitting display device and a method of aging the same.
2. Description of Related Art
In general, a plurality of organic light emitting display panels are formed with one mother substrate, scribed and separated into respective panels. That is to say, in order to more effectively manufacture a large number of organic light emitting display devices, a so-called sheet-unit manufacturing method has been developed, which includes: forming panels of a plurality of organic light emitting display devices with one mother substrate and scribing it into separate panels.
The independently divided panels of the organic light emitting display devices are generally separately inspected, where each of the respective panels is inspected using an apparatus for inspecting a panel unit. However, the inspection process can be inefficient since the inspection needs to be separately carried out on each of the panels.
Accordingly, it is generally required that the panels of a plurality of the organic light emitting display devices be inspected sheet by sheet before being separated from the mother substrate.
The inspection of the panels that is to be carried out sheet by sheet as described above can include a lighting inspection, a leakage current inspection, etc. Also, an aging process may be carried out sheet by sheet to reduce the manufacturing time and cost.
In display devices, a newly formed organic light emitting diode is rapidly deteriorated at the beginning of driving, and then is gradually stabilized. The aging process is carried out to suitably compensate for the deterioration of the organic light emitting diode by first driving the organic light emitting diode and adjusting its drive voltage prior to the product release.
Therefore, driver power sources and/or drive signals are supplied to each of the panels for the aging process.
That is to say, a predetermined electric current flows in the organic light emitting diodes by supplying the driver power sources and/or drive signals to a plurality of the panels sheet by sheet, and by particularly supplying an aging signal to data lines of each of the pixels.
In order to reduce the aging time, the current value applied to each of the panels over a predetermined time period is increased. However, the increase in current value results in increased or aggravated voltage drop (IR drop) in sheet wires that supply driver power sources and/or drive signals to each of the panels.
In particular, the voltage drop in the sheet wires, e.g., to supply pixel power sources (ELVDD and ELVSS) supplied as a DC power source, is higher than other drive signals and/or reference power voltages (VGH and VGL) supplied for a predetermined time.
That is to say, the pixel power sources (ELVDD and ELVSS) having different voltage levels may be supplied to each of the panels since the voltage drop of the pixel power sources (ELVDD and ELVSS) varies according to the position of the panels formed on the mother substrate. This may cause driving problems or bright defects in some panels when aging is carried out sheet by sheet.
In particular, when the voltage drop of the first pixel power source (ELVDD) is severe, the voltage difference of ELVDD from the first reference power voltage (VGH) of a scan driver is different in every panel, which results in the driving problems and/or bright defects in the panels.
In order to address the above problems, the electric current applied to each of the panels should be low during the aging process, but the aging time may be increased.